In the A549 xenograft tumor model, we showed that 4-CBA treatment moderately inhibited tumor growth, and combining 4-CBA with RT markedly suppressed tumor growth (Fig. 6j, k), which correlated with increased 4-HNE staining (but not with phospho-H2AX or cleaved caspase-3 staining) in these tumor samples (Fig. 6l, m and Supplementary Fig. 7a–d). Here, H2AX is linked to neoplasm.